Pivot4J provides a common Java API for OLAP servers which can be used to build an analytical service frontend with pivot style GUI. It aims to leverage mature but now discontinued JPivot project's codebase to make it a general purpose OLAP API library which is independent of any particular GUI implementation.
For a long time, JPivot has remained as a de facto standard for creating a pivot grid style OLAP frontend application in Java language. However, as the project is no longer actively maintained for now, advance of new web technologies has made its JSP-based approach look quite outdated.
Moreover, JPivot was never designed as a common API for OLAP even it included lot of useful backend implementations for connecting to and work with XMLA and Mondrian servers.
As many BI developers felt the need for more modern and generic API for OLAP in Java, Olap4J has emerged as a combined effort by various commercial and open source projects to fill this gap.
Pivot4J project has been started as a fork and major refactoring effort of JPivot to combine the best parts of both libraries. It replaced JPivot's legacy backend implementation with Olap4J while leveraging its mature query transform API. And also Pivot4J has done extensive refactorings to make its codebase more modern and maintainable.
Pivot4J itself does not mandate to use any specific technology to build an UI application with it. Rather. it's designed as an easy to use model and abstract UI layer for creating such applications using any technologies like JSP, JSF, GWT, or even client side graphical toolkits like SWT or Swing.
If you have any question or suggestion for the project, please leave your message at the support forum.